The present invention relates to a new and improved joint assembly and more specifically to a ball and socket type joint assembly which is advantageously utilized in a vehicle steering system.
Known vehicle steering systems commonly include a plurality of links which are interconnected by ball and socket type joints. When the vehicle is to be turned, a pitman arm is moved to actuate the linkage and effect turning movement of steerable wheels under the influence of forces transmitted through the ball and socket joints. Upon interruption of the steering action, the wheels are returned to a straight ahead condition under the influence of the various known forces which are due to many different factors, including kingpin inclination and caster. In some cases these forces may not be enough to return the steerable wheels all the way to the straight ahead position.
One known arrangement for supplementing the forces tending to return a vehicle steering linkage to the straight ahead position is disclosed in U.S. Pat. No. 1,918,520. The arrangement disclosed in this patent includes a cam which is connected with a pitman arm and is disposed between a pair of seat elements. One of the seat elements is fixedly connected with a drag link. The other seat element is pressed against the cam by a biasing spring. Upon actuation of the pitman arm, the cam is rotated and shifts the movable seat against the influence of the biasing spring. As the movable seat is shifted, the center of the pitman arm is moved relative to the drag link. Of course, this results in a variation in the effective overall length of the drag link with a resulting change in the geometry of the steering linkage. Other known systems for supplementing the forces tending to return a steering linkage to a straight ahead condition are disclosed in U.S. Pat. No. 1,967,288.